Do patients initiate therapy? Primary non-adherence to statins and antidepressants in Iceland

Background: Primary non-adherence occurs when a drug has been prescribed but the patient fails to have it dispensed at the pharmacy.

Aims: To assess primary non-adherence to statins and antidepressants in Iceland, the association of demographic factors with primary non-adherence, and the time from when a prescription is issued until it is dispensed.

Methods: Data on patients receiving a new prescription for a statin or an antidepressant from the Primary Health Care database were linked with dispensing histories from The Icelandic Prescription Database. The proportion of patients who did not have their prescription dispensed within a year from issuing (primary non-adherent) was assessed, as well as the time from issue until dispensing. Associations between demographic factors and primary non-adherence were estimated using logistic regression.

Results: The overall primary non-adherence was 6.3% and 8.0% for statins and antidepressants, respectively. The majority of patients had their prescription dispensed within 7 days (85% for statins, 87% for antidepressants). Being disabled and receiving a prescription for an expensive drug was associated with higher rates of primary non-adherence.

Conclusion: The rate of primary non-adherence to statins and antidepressants in Iceland is low. Vulnerable groups such as the disabled should be given special attention when new drugs are prescribed.